Symposium on my cyber operations book

The online academic journal Questions of International Law has just published a symposium on my book Cyber Operations and the Use of Force in International Law (which is now available also in paperback). Two excellent scholars, Prof. Christian Henderson (Sussex University) and Dr. Emanuele Sommario (Scuola Superiore Sant’Anna – Pisa) discuss my analysis of the jus ad bellum and jus in bello issues arising from the use of cyber technologies. Their reviews are themselves very interesting contributions to the debate on cyber security and well worth reading.

Another excellent (and very positive!) review of my book has been written by Vincent Roobaert and has been published in the latest issue of the NATO Legal Gazette.

Panel event on nuclear weapons

Those of you who find themselves in the London area on 28 October may be interested in this panel event on nuclear weapons that I am chairing. The panel will discuss the legality of the use of nuclear weapons under different international law regimes almost 20 years from the Advisory Opinion of the International Court of Justice. The event will also celebrate the book launch of: Nuclear Weapons Under International Law, G. Nystuen, S. Casey-Maslen and A. Golden Bersagel eds (Cambridge University Press, 2014). Attendance is free, but please register by emailing Eliza Watt.

Until silence

Children and babies—whether born or unborn—suffer immensely in any armed conflict. Mental trauma from witnessing human wasting, which no person should really be exposed to anymore. Physical injuries that scar the young ones for the rest of their lives, even if a sense of normalcy could ever be recaptured. And death, often considered the worst possible outcome, but nonetheless a fortuitous escape from a lifelong suffering inflicted by a senseless war ripping apart the early stages of their far too many young lives. For the survivors—bereft parents and mothers of the stillborn one—deep-reaching psychological wounds far beyond consolation.

Until the silence says goodbye

Addressing her companion after a mutual acquaintance, a British naval officer who had served in World War 1, suddenly passed away in 1923, Vera Brittain (Testament of Youth, Chapter XXII, 4) wrote:

I don’t think victory over death is anything so superficial as a person fulfilling their normal span of life. It can be twofold; a victory over death by the man who faces it for himself without fear, and the victory by those who, loving him, know that death is but a little thing compared with the fact that he lived and was the kind of person he was … That’s why those war victories with which I was especially associated are still incomplete. That the people faced their own deaths without fear I have no doubt. It is through me that the victory is incomplete, because I cannot always quite feel that their deaths matter less to me than the fact that they lived, nor reconcile their departure, with all their aspirations unfulfilled, with my own scheme of life.

Having lost her fiancé, two brothers and a close friend in the Great war, she was still struggling make sense of death, despite a self-induced mental numbness to cope in a post-war British society that had no time or space to embrace its many scarred veterans with the human carnage she saw firsthand as a voluntary nurse.

No pantomime of time to heal…

For the unborn child or infant physically or psychologically mauled by detonating bombs or shells, there is no victory for having lived that parents could savour. Chemical weapons add to that despair: a person living under their threat has no sense of being able to escape them. There is simply no place to run (to paraphrase Tim Cook’s magnificent book on Canadian soldiers’ adaptation to survive under a perpetual gas blanket during World War 1).

Hurt and fear are overwhelming emotions. Children and gas, when combined, allow for easy, but powerful manipulation of public opinion beyond the battlefield, often for purposes that have little bearing on relieving the plight of those actually facing the threats. Add a couple of graphic pictures; throw in one or two names to make the suffering tangible and direct public emotions to these few foci in order to momentarily blur out the 150,000 fatalities and millions of other casualties shared by all sides in the Syrian civil war. Can a policy maker or shaper fail to respond to such concentrated emotion? This is why I reacted strongly to the unsubstantiated claims that sarin exposure was causing the deformed babies in ‘Must the Belgian babies be bayoneted all over again?

Today, a week or so after The Telegraph (London) and The Daily Star (Beirut) ran their respective ‘scoops’, no additional claims, no new names of children from the Ghouta area, have surfaced. A few media outlets reported on the original stories, but to the best of my knowledge, nobody seems to have delved further into the matter. Claims of sarin’s mutagenic properties appear to have vanished into thin air.

Survive to die alive

In contrast, other factors that may explain the incidence of miscarriages and malformed babies have come to the fore: prolonged extreme stress, concussion, exposure to high levels of dust, malnourishment, unsanitary conditions (at home, in shelters or in hospitals), etc.

Last December, many months before the sarin claims, a trained paediatrician with 20 years experience working Médecins sans frontières attributed the malformations in Syrian infants she was treating to possible deprivation of folic acids. No or insufficient intake during especially the first four weeks of a pregnancy profoundly compromises the neurulation process, which in turn leads to severe congenital deformity.

If this doctor’s surmise is correct, then the rising incidence of stillborn or malformed babies testifies to the dreadful state of Syria’s health system more than anything else.

She also described the wrenching plight of two pregnant women caught up in aerial bombing on their way to the market one sunny day. One lost her baby in her struggle to survive …

No hint of sarin or chemical warfare in her accounts.

There is simply no need to add gas to feel the pain of Syrian mothers …


[Cross-posted from The Trench]

Green is the colour

The Organisation for the Prohibition of Chemical Weapons (OPCW) is about to investigate the various allegations of the use of chlorine in Syria over the past few weeks. It is the right decision. It is the only decision possible in view of the many witness accounts and footage available on internet sites. However, the hope that the announcement of the fact-finding mission on 29 April might deter the perpetrator from future chlorine attacks was quickly dashed: a new chlorine bombing took place a day later.

The symbolism of the date cannot be overstated. 29 April was the 17th anniversary of the entry into force of the Chemical Weapons Convention (CWC). 29 April is the UN’s annual Day of Remembrance for all Victims of Chemical Warfare. And now, 29 April is also the day on which for the first time the potential violation of the ban on the use of chemical weapons (CW) by a state party to the CWC was officially recognised. A mere six months after Syria joined the convention. And 99 years after chlorine ushered in the age of modern chemical warfare.

On the same day, a British newspaper, The Daily Telegraph, felt the need to headline that it had the proof that Assad launched the chlorine attacks. It caused a stir, not in the least because the article ended with the claim that the newspaper’s investigation was on a par with OPCW procedures. Hardly.

No stranger to the battlefield of world opinion

It is worth recalling that initial accounts on the chemical attack at Khan al-Assal (near Aleppo) on 19 March 2013 referred to chlorine. Early press reports mentioned 26 fatalities, a figure that would eventually rise into the low thirties, and scores of otherwise harmed individuals. I was not convinced that the observed effects correlated with claims about the agents used. In a March 2013 brief for the EU Institute for Security Studies I wrote:

This claim is intrinsically problematic. Exposure to chlorine stored in a warehouse or near a production installation hit by a shell could account for respiratory problems and skin irritation, but not for a high number of fatalities. One would need a very high volume of the agent to obtain lethal doses in open air; the explosion would most likely destroy part of the agent; and highly recognisable evidence of corrosion at the site of attack could not be missed.

More recent accounts specify that Islamic extremists filled a home-made rocket with chlorine dissolved in a saline solution. The agent would thus amount to Eau de Javel (bleach). Even in its highest industrial concentration of 40%, the agent cannot explain the fatalities, even if one were to assume that a very large number of home-made rockets hit the target in a tight cluster.

A month later, I remained just as unconvinced. In the meantime, having reviewed all CW references I had collected since the start of the Syrian civil war, I was struck by how stories on a particular incident may change with time. As a rule of thumb, everything ultimately turned into sarin. And as suggested in the quote above, sarin could become bleach. It is worth retracing that metamorphosis.

The Khan al-Assal attack of 19 March prompted the Syrian Government to request the UN Secretary General to conduct an investigation of alleged use. As already mentioned, reports at the time were referring to chlorine or witnesses recalling a chlorine smell. Chlorine was also what the Syrian government reportedly cited in its letter to Ban Ki-moon. Already early in December 2012, the Syrian Foreign Ministry had warned of possible insurgent use of CW in letters to the UN. It alluded to a Syrian-Saudi factory SYSACCO near al-Safirah (southeast of Aleppo), which had just been captured by militants from the jihadist Al-Nusra Front. That factory produced  sodium hydroxide (caustic soda) and hydrochloric acid (HCl). Not only did this claim prepare a plausible foundation for the chlorine allegations three months later, it also gets close to the bleach (sodium hypochlorite), commercially known as Eau de Javel in Europe.

Four days after the alleged attack we learn that ‘the Syrian military believe that a home-made locally-manufactured rocket was fired, containing a form of chlorine known as CL17, easily available as a swimming pool cleaner. They claim that the warhead contained a quantity of the gas, dissolved in saline solution’. Now, what form of chlorine is Cl17? A look at the Mendeleev’s Periodic Table teaches us that Cl is the chemical abbreviation of chlorine and 17 is its chemical number. However, this demystified CL17 is contained in a saline solution, which is, of course, sodium hypochlorite. I use it to disinfect my toilet. Eau de Javel as a chemical warfare agent, that was new to me. (However, do note the source of that story.)

So, please forgive me if I seem to demand a higher level of convincing.

Questions I would like to see answered

  • From some of the footage available on the internet, I do think that a toxic substance must have affected a number of people. However, I am less sure about the more precise elements in the accusations. For example, based on the pictures of one of the flasks, I gather that a substance (in this case, liquid chlorine, I presume, but then letters with white powder are also often marked ‘anthrax’) was contained in a small industry-standard vessel (apparently of Chinese origin & and marked Cl2). What I would like to know is how much explosive it would take to break open such a container? How much chlorine (if this is what was inside) would have been destroyed or burned by that explosion? What are the dynamics of chlorine release in the scenario that the amount of explosives is sufficient just to break the seal / valve of the vessel? I have been told that such an amount would be very small, but how does the resulting aperture affect the dynamics of gas release? Was the vessel contained inside a drum (i.e., a confined space), as some reports suggest? If so, how does that affect the dynamics of the explosion and gas release? What would the impact of an explosive devise have on the rate of release of the chlorine and how much of the chlorine would actually remain after the rupture of the container?
  • How much chlorine (if this was what it was) was inside the vessel? How would sufficient chlorine be built up locally to seriously injure or even kill people? In what environment was the chlorine released (e.g., closed space of a room or outside in the open air)? Chlorine is perceptible to humans in very low concentrations, so why would people remain in close vicinity of the devise long enough to absorb a harmful dose of chlorine? Following the blast, I have been told, people in close proximity of the bomb may be dazed and confused and in their disorientation may consequently not escape from the area. Was this the case?
  • Would an industry-standard container rupture simply by dropping it from a helicopter?
  • One film clip on Brown Moses’ blog shows a helicopter dropping something, followed by a – in my mind – big flash. Would chlorine withstand the forces and heat of such a detonation? Detonation of chlorine was pretty ineffective in Iraq (at least as regards the impact of chlorine on the targeted group of people).
  • Are there any reports of corroded metals in the vicinity of the area of release? (Moisture in the air acts as a catalyst for chemical reactions with chlorine, and the agent is very aggressive on metals and alloys.)
  • Why do press reports refer to a ‘yellow’ smoke or powder (as one Beirut-based journalist described the observations to me)? Chlorine tends more towards pale green, sometimes with a yellowish hue. However, the yellow might dominate in a sun-swamped environment and an overall sandy-colour backdrop. I do not know. A BBC clip (2nd clip, middle article, final seconds) posted on 28 April, shows yellow smoke from a barrel bomb attack in which no chlorine was used. So, can we see similarities of symptoms and phenomena between different types of attack, but which witnesses do not or cannot differentiate? Another example: as for the reports of a chlorine smell near the scene of the Khan al-Assal attack in March 2013, chemical weapons expert and chief operating officer of SecureBio, Hamish de Bretton-Gordon, then said that conventional high explosives can also produce an odour which might be mistaken for chlorine.
  • Would one expect a hissing sound as the chlorine under pressure escapes from the container? Have we seen any such witness accounts?
  • Are we looking at a case of what I call ‘opportunistic use of toxic chemicals’, where people (government soldiers, their allies, or insurgents) took hold of containers at an industrial site and improvised a new device of war? In other words, are we looking at a case of deliberate preparation for chemical warfare by whoever is responsible for the events?

A good call

The OPCW Director-General’s decision is the right one. Ambiguity and speculation must be removed—and fast. The lack of precise timing (or explanation of the necessary preparations and precautions) in the OPCW press statement is worrying, and not just because this is the first time the organisation is called upon to launch an investigation of use all by itself (in previous investigations the OPCW assisted the UN Secretary-General, as Syria was not yet a party to the CWC). Chlorine is a very volatile element, so the critical question is how long the agent might reside in the soil, on other surfaces or inside containers? The answer is not long, especially not in the heat of Syria.

Still, the exercise should not be futile. Investigations of alleged use typically apply various methods (medical analysis, identification of plausible witnesses and corroboration of individual stories, matching pictures and film footage based on the stories by the carefully selected witnesses, etc.), whose independent results should contribute to building a more or less consistent picture of events. The OPCW inspectors would deploy sophisticated detection equipment. Any evidence brought back from the incident sites would be subject to strict procedures to preserve the chain of custody and then divided over multiple OPCW-certified laboratories for analysis.

And oh, just as a small afterthought: with an OPCW investigation, one of course does not have to wonder who has paid the piper.

[Cross-posted from The Trench]

After 99 years, back to chlorine

Today is the 99th anniversary of the first massive chemical warfare attack. The agent of choice was chlorine. About 150 tonnes of the chemical was released simultaneously from around 6,000 cylinders over a length of 7 kilometres just north of Ypres. Lutz Haber—son of the German chemical warfare pioneer, Fritz Haber—described the opening scenes in his book The Poisonous Cloud (Clarendon Press, 1986):

The cloud advanced slowly, moving at about 0.5 m/sec (just over 1 mph). It was white at first, owing to the condensation of the moisture in the surrounding air and, as the volume increased, it turned yellow-green. The chlorine rose quickly to a height of 10–30 m because of the ground temperature, and while diffusion weakened the effectiveness by thinning out the gas it enhanced the physical and psychological shock. Within minutes the Franco-Algerian soldiers in the front and support lines were engulfed and choking. Those who were not suffocating from spasms broke and ran, but the gas followed. The front collapsed.

The impact of this gas attack surprised the German Imperial troops too. Their cautious advance behind the chlorine cloud, their hesitation in the confusion about what was happening despite having secured their initial objectives within an hour, and their halt after darkness fell meant that they almost immediately lost the strategic surprise. They would never regain it.

A first generation warfare agent in worldwide industrial application

How ironic it is that today, almost a century later, the latest chemical warfare allegations in the Syrian civil war concern chlorine once again. Everybody knows about the dangers of the chemical element, but nobody really considers it any longer as a militarily useful agent. At least not in standard warfare scenarios.

Chlorine and derived products are in massive industrial production. According to the World Chlorine Council, there are more than 500 chlor-alkali producers at over 650 sites around the globe, with a total annual production capacity of over 55 million tonnes of chlorine. Based on the low threat assessment and its wide relevancy to the chemical industry and trade, the Chemical Weapons Convention (CWC) does not even list it in Schedule 3 of toxic chemicals (Phosgene, another widely used chemical and World War 1 agent, is).

An oversight by the CWC negotiators? Hardly. Books on the toxicology and treatment of chemical warfare agents published between 1992—year of successful conclusion of the negotiations—and 1997—year of entry into force of the CWC—hardly mention chlorine. Chemical Warfare Agents, edited by Satu Somani (Academic Press, 1992), presents a few scattered references, mostly in relation to other agents or public health. Another book featuring the same title, written by Timothy Marrs, Robert Maynard and Frederick Sidell (Wiley, 1996), gives it a four-line acknowledgment in the opening historical section. And the monumental Medical Aspects of Chemical and Biological Warfare, edited by Frederick Sidell, Ernest Takafuji and David Franz (Office of the Surgeon General, US Army, 1997), accords it about two pages out of 721 in a subsection entitled ‘Historical War Gases’.

Today, chlorine is mostly viewed as a public health or environmental hazard resulting from occupational exposures, industrial accidents or the malfunctioning of pool chlorination systems.

Back to World War 1

It goes without saying that during and after World War 1 perceptions of chlorine as a combat agent were quite different. Despite having been replaced by much more potent toxic chemicals, belligerents released chlorine gas until the final month of the war. Considering that the first contingents of the American Expeditionary Forces arrived in Europe in June 1917, but saw their first major military engagements in May/June 1918, the US War Department registered and examined 838 ex-service men who had been gassed with chorine (and survived their experience). A closer medical examination of 98 victims to assess the long-term effects of exposure suggests that all US chlorine casualties were affected between July and October 1918. It is interesting to note that Maj. Gen. Harry Gilchrist, Chief of the Chemical Warfare Service, and Philip Matz, Chief of the Medical Research Subdivision of the Veterans’ Administration, devoted half of their medical study, The Residual Effects of Warfare Gases (War Department and US Government Printing Office, 1933), to chlorine, mustard being the other agent of their investigation.

Their description of chlorine remains interesting, because it departs from its utility as a warfare agent, rather than as a public health hazard. The element is almost 2.5 times heavier than air, which means that it will cling to the surface and sink into depressions. At 15° C liquefaction requires 4-5 atmospheres pressure. Upon release at 25° C, one litre of liquid chlorine will yield 434 litres of chlorine gas. Moisture stimulates the element’s chemical action, so the liquid gas must be thoroughly dehydrated for storage in steel cylinders.

Concentration and length of exposure both play a role in the physiological action of chlorine and their effects on humans and animals. The authors noted that ‘a concentration of 1–100,000 of chlorine gas is noticeable, 1–50,000 may cause inconvenience, while a concentration of 1–1,000 may produce death after exposure for five minutes’. (The numbers correspond to 0.01 mg/ml; 0.5 mg/ml and 1mg/ml respectively.) Experimental studies on dogs (carried out to determine the types of lesions various concentrations of chlorine will produce) showed that the animals died within 72 hours from acute effects at concentrations of 2.53 mg/l and higher. These concentrations were labelled as lethal. A small percentage of the animals recovered within a week. A concentration of 1.9–2.53 mg/l increased the recovery rate markedly, whereas dosages below the 1.9 mg/l were rarely fatal. Recovery rates were markedly faster at lower concentrations.

Concentrations required for injury and death are relatively high. For comparison, in the section on mustard (dichlordiethyl sulphide) Gilchrist and Matz deemed this oily compound to be 50 times more toxic than chlorine. It can be deadly in concentrations from 0.006 to 0.2 mg/l, but they considered 0.07 mg/l at an exposure of 30 minutes to be the lethal concentration.

Rewind to March 2013

Syria, just like any other country with a relatively advanced chemical industry, produced chorine in large quantities before the civil war. Readers will recall that early reports of chemical attacks at Khan al-Assal, west of Aleppo, in the middle of March of last year mentioned a strong smell of chlorine. To the east of Aleppo, there was a chlorine production facility (which the Jubhat Al Nusra, a jihadist rebel group ideologically similar to Al Qaeda, reportedly took over in December 2012). However, accounts also mentioned scores of fatalities, which would be inconsistent with a chlorine-filled rocket warhead. I have always been sceptical about those claims, precisely because of the agent’s chemical properties and physiological action. At the time, descriptions did not fit the claimed agents, whichever these might have been.

The need to compress the agent into a liquid has ramifications for delivery: the container must be sufficiently strong to withstand several atmospheres of pressure, and if dropped from an aircraft, sufficiently thin for the skin to break open. It must also be large enough so that a lethal concentration can be built up for a sufficiently long time. Given that humans smell chlorine at very low concentrations, the chances that they will remain at the site of impact are remote. The element is also not colourless; in fact, its name derives from the ancient Greek ‘khloros’, meaning pale green.

The same goes for rocket delivery of the warfare agent. Shells were attempted during World War 1, but this method for chlorine discharge was quickly abandoned in favour of much more potent munition fillings, such as phosgene.

So, it would be good to get more details on the recent incidents and review them in the light of possible chlorine delivery. Please note that I do not deny the possibility of toxic incidents over the past few weeks, but I would just like to see the various facts reconciled with the claimed chain of events. Given that Russian Foreign Minister Sergey Lavrov and French President François Hollande have once again waded into the controversy, politicisation of the ‘truth’ cannot be far away, alas.

Back to where it all started

So, as we reflect on that fateful 22 April in 1915, the sad thought is that chlorine is back, or at least, that people feel that chlorine is back as a possible lethal combat agent.

Allegations fly, but if confirmed, the incidents would be the first acts of chemical warfare committed involving a state party to the CWC. If Syria’s accusation of insurgent use is correct, then the government has every opportunity to demand an investigation from the OPCW and request assistance. If the insurgents’s claim of government use is correct, as non-state actors they cannot request the OPCW anything. However, any state party to the convention can demand an investigation of alleged use by the OPCW, and the Syrian government has no right of refusal (Verification Annex, Part XI). The opposite would be a serious material breach of its treaty obligations and tantamount to an admission of guilt. Or, the states parties can determine that the claims are insufficiently substantiated to warrant an investigation. In which case, it would be nice if they all were to sing the same tune.

So, which way shall the international community have it? The principal long-term casualty of those political games might be the CWC, even though, admittedly, we are still far away from the death knell that 22 April 1915 sounded for the 1899 Hague Declaration (IV, 2) concerning asphyxiating gases.


Several recent reports have suggested that because chlorine or other toxicants, such as riot control agents or incapacitants, are not listed in one of the schedules, they are not covered by the CWC. This is a major error. Any chemical which through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals is a chemical weapon, according to Article II of the CWC. This is the default position. There are only four categories of purposes (Art. II, 9), under which a toxic chemical would not be considered a weapon.


Cross-posted from The Trench.]

Is there a “cyber war” between Ukraine and Russia?

I have just published a blog post addressing this question in the OUP Blog. In the post, I apply some of my book’s findings to the current Ukraine-Russia crisis. As always, comments are welcome.

My new book on cyber operations is out


My book on Cyber Operations and the Use of Force in International Law has just been published by Oxford University Press. If you are interested in ordering a copy, please click here, or, if you prefer the US OUP website, here.

Here is the abstract:

The internet has changed the rules of many industries, and war is no exception. But can a computer virus be classed as an act of war? Does a Denial of Service attack count as an armed attack? And does a state have a right to self-defence when attacked in cyberspace? With the range and sophistication of cyber attacks against states showing a dramatic increase in recent times, this book investigates the traditional concepts of ‘use of force’, ‘armed attack’, and ‘armed conflict’ and asks whether existing laws created for analogue technologies can be applied to new digital developments.

The book provides a comprehensive analysis of primary documents and surrounding literature to establish whether and how existing rules on the use of force in international law apply to cyber operations. In particular, it assesses the rules of the jus ad bellum, the jus in bello, and the law of neutrality (whether based on treaty or custom), and analyses why each rule applies or does not apply in the context of cyber operations. Those rules which can be seen to apply are then discussed in relation to each specific type of cyber operation. The book addresses the key questions of whether a cyber operation amounts to a use of force and, if so, whether the victim state may exercise its right of self-defence; whether cyber operations trigger the application of international humanitarian law when they are not accompanied by traditional hostilities; what rules must be followed in the conduct of cyber hostilities; how neutrality is affected by cyber operations; and whether those conducting cyber operations are combatants, civilians, or civilians taking direct part in hostilities. The book is essential reading for everyone wanting a better understanding of how international law regulates cyber combat.

The book also contains a thought-provoking Foreword by Prof. Yoram Dinstein.